Which of the given procedures should be followed before applying paint onto different components of a building? i) Chalking ii) Flaking iii) Removing blisters iv) Surface wetting
- AOnly (i)
- B(ii) and (iii)
- C(i), (ii) and (iii)Correct
- DAll of (i), (ii), (iii) and (iv)
Solution
Concept
Chalking, flaking and blistering are common paint defects. They must be removed or treated before a new coat is applied.
Step-by-step solution
1. Chalking: powdery layer on old paint. It must be brushed off before repainting. 2. Flaking: loose paint pieces. They must be scraped off. 3. Blisters: bubbles in the paint film. They must be cut and removed. 4. Surface wetting: mainly done for cement paint or whitewash, not for normal oil or enamel paint. It is not a general step. 5. So (i), (ii) and (iii) are the correct set. Answer (C).
Explanation
Chalking, flaking and blistering are defects of old paint. Before repainting, these defective layers must be removed so the new paint can bond well. Wetting the surface is not a general rule, because most paints need a dry surface.
Why the other options are wrong
A: Leaves out flaking and blisters. B: Leaves out chalking. D: Surface wetting is not a general step, because oil paints need a dry surface.
Shortcut
Chalking, flaking and blistering are all defects, so group them together and pick (i), (ii), (iii).
Common mistake
Choosing 'all' because wetting is done before cement paint or plastering.
Correct answer: C) (i), (ii) and (iii)